Portable toilet seat



FIG. 1 is a perspective view of the portable toilet seat, showing my new design;

FIG. 2 is a front elevation view thereof, with a rear elevation view being a mirror image thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a right elevation view thereof; and,

FIG. 6 is a left elevation view thereof.

The broken line showing of environment is included for the purpose of illustrating the portable toilet seat and forms no part of the claimed design. 

I claim the ornamental design for a portable toilet seat, as shown and described. 